I had success with a roller, paint pan and some joint compound. Add some water to the compound to thin it out. Do some practice rolls on some scrap, then go for it. While it's wet you can keep adjusting your technique and the mix.

Looks like a sponge was used. What I would do is practice on some scrap pieces until you got a good match. Appears that a sponge is dipped into some slightly thinned compound and dabbed on. Sponge, roller, or other, do whatever gives you the match.

"Appears that a sponge is dipped into some slightly thinned compound and dabbed on."

And the way to cover a large area quickly is with a sponge roller.

I still have a couple hanging around in the basement.

Texture paint and a sponge roller produces this affect also.

Lowes, sells a tool, called a mud stomper, that will do that texture for you. It is a rounded brush type thing and comes with a short handled pole, but you can buy a longer handle and do it all from the floor, if necessary. It works very easily. Your texture, looks a bit less than what mine is, so your mud is put on a bit lighter than mine. The tool, is what makes the pattern on your sheetrock. You cant tell, the repair from what was there, on mine. You can find directions for using it online. Good Luck

I came here today looking for info on how to duplicate "knock down" texture and saw this post right away. I figured I'd jump in since were on the subject and maybe someone has a trick to duplicate Knock down. I have some big 7 x 20 patch areas. I have sanded but it is still a bit high should I sand so it's less then the area around it? TIA

I recall seeing Tom Silva on This Old House replicate it by using a wood float and skipping the float on the ceiling with mud.

But if your patch is already dry and overfilled, I'm not sure what to tell you. Maybe sand it down, scratch it as necessary, and poke it a bit, too.

Thanks homebound I should not have filled in so much. Guess I got some sanding to do..... boo

JJaazzy - look for a roller that has loops of stuff on it.

Spread a thin layer of drywall with a blade, then roll through it slowly with the roller.

Leave it like that to duplicate the soft peaks, or let it dry a bit and lightly scrape with a knife for knockdown.

Oh cool that makes a lot of sense. Maybe I will make up something here with strips of fabric on a roll or something I have such a tiny space but that would give me the negative areas (pushed in areas) I need. And then following up with the flat blade. I still have to get up there and sand down all the excess away. It's on the ceiling so it's a real pain. Thanks.